The hand part doesn't worry me, so you're asking the wrong person. Conventions, like gentlemen wearing hats, come and go. It's when the Church jetisons the tenets of the Faith that I see red.
That said, if you don't want your child to take Communion that way, I can't see any reason why the priest shouldn't observe your wishes. I'd simply make the request, firmly and politely. And I'dd tell my boy why I think the traditional method is the right method.
Good luck.
Really?
I remember being taught (in 1971) that the host was not to be chewed, just allowed to dissolve on your tongue. That was after the demand was for the Holy Eucharist to be received kneeling.
I just don't see the reverence for receiving God (as we are taught) in the hand--I guess I've seen too many slouching, irreverant people during Communion to turn me against it. It seems to me that there is too much of this putting God on OUR human level (and I got this education in the 1970s--when I was in elementary school) post V2 versus the proper reverance and respect that we owe Him.